The government has confirmed a second farm in Egham has tested positive for foot and mouth disease.
Chief veterinary officer Debbie Reynolds announced today that tests on livestock from the second farm had revealed they were contagious.
The animals were culled last night as a "precautionary measure", bringing the total number slaughtered during the September outbreak to 940.
Yesterday, the environment secretary Hilary Benn said the virus is "likely" to be the same strain that emanated from the Pirbright laboratory last month.
A national movement ban is currently preventing farmers from transporting livestock, during what should be their busiest time of year.
There was some relief as restrictions surrounding a third farm in Norfolk were removed, following negative test results on livestock there.
Ms Reynolds said a detailed epidemiological investigation is currently underway, with disease control remaining a top priority.
One of the country's largest lamb sales had to be cancelled at Hawes Auction Mart today due to the movement restrictions.
As the biggest sale in England it would normally bring in £1.5 to £1.7 million in turnover. In addition to that, it is expected the local economy will suffer another £300,000 or £400,000 in losses.
The government has been urged to consider a vaccination strategy.
Patrick Holden, the director of the Soil Association, said: "There are thousands of farmers all over the country who are in a desperate state, worried about how long the restrictions are going to go on.
"If you look across the water towards Holland, if they had even had one outbreak they would immediately vaccinate, and in the 2001 outbreak within three days they had vaccinated 100,000 animals."
Mr Holden warned the failure to vaccinate could exacerbate the situation.
He continued: "Why not start today? Why not create a firebreak community around the infected farm? That way you give no chance of further spreading and I would say create a very strong justification for reducing the restrictions further afield."
The National Farmers Union is pressuring the government to bring forward some support payment to assist farmers.
Malcolm Corbett of the NFU argued: "We feel government has a responsibility here, a moral responsibility, because this is not of the farmers' doing.
"We're appealing to the government to pay upfront some of the single farm payment that would be coming on to these farms as soon as possible.
"We are not asking for anything that wouldn't be coming to us anyway".